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Speciation of heavy metals in sediments from Baihua Lake and Aha Lake.

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ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
Published online 25 May 2009 in Wiley InterScience
(www.interscience.wiley.com) DOI:10.1002/apj.307
Special Theme Research Article
Speciation of heavy metals in sediments from Baihua Lake
and Aha Lake
Xian-fei Huang, Ji-wei HU,* Jia-jun Deng, Cun-xiong Li and Fan-xin Qin
Guizhou Provincial Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal
University, Guiyang, 550001, China
Received 20 August 2008; Revised 3 February 2009; Accepted 22 February 2009
ABSTRACT: Baihua Lake and Aha Lake are both drinking-water sources for Guiyang City, the capital of Guizhou
Province in southwestern China. In the present research, chemical speciation of chromium (Cr), copper (Cu) and zinc
(Zn) in the sediments from these two lakes was studied based on the sequential extraction procedure developed by
Tessier et al ., and organic matter (OM) was determined by ignition method. The results obtained are as follows:[1] The
organic matter amounts in sediments from Baihua Lake and Aha Lake ranged from 11.62 to 18.02% and 8.48 to
13.90%, respectively;[2] Cr and Zn were mainly distributed in residual phase, while Cu mainly existed in oxidizable
and residual phases;[3] Levels of Cu distributed in oxidizable phase in sediments from Baihua Lake were higher than
those from Aha Lake;[4] Mobility, bioavailability, and toxicity of Cu were low in comparison with Zn and Cr, because
Cu was mainly distributed in oxidizable and residual phases in which heavy metals mobility was lower than in the other
phases. The Pearson’s correlation coefficient between organic matter and Cr in oxidizable phase of the 20 sediment
samples collected from the two lakes was up to 0.604 (p < 0.01).  2009 Curtin University of Technology and John
Wiley & Sons, Ltd.
KEYWORDS: Baihua Lake and Aha Lake; sediments; sequential extraction procedure; speciation of heavy metals
INTRODUCTION
There are various media that were available for investigation of contaminants in aquatic ecosystems, such
as water, biota, suspended material, and sediments.[1]
Sediments have attracted a significant attention mainly
because they have always been considered as a
sink and reservoir for a variety of environmental
contaminants,[2,3] and also usually provide a record of
catchments input into aquatic ecosystems.[4] In addition,
it has been recognized that aquatic sediments absorb
persistent and toxic chemicals to levels many times
higher than the water column concentration.[5] When
circumstances of sediments are changed, these contaminants would be released into the water column.
Heavy metals have been known to cause numerous
adverse effects to humans and ecological systems, and
pollution of aquatic systems with heavy metals has
aroused a huge public concern. Heavy metals may be
introduced into aquatic systems through many ways,
such as industrial and municipal wastes, atmospheric
*Correspondence to: Ji-wei HU, Guizhou Provincial Key Laboratory
for Information System of Mountainous Areas and Protection of
Ecological Environment, Guizhou Normal University, Guiyang,
550001, China. E-mail: jiweihu@yahoo.com
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
emissions, metal corrosion products, and leached agricultural chemicals. To study heavy metals pollution,
the total concentration of a heavy metal may be useful
as a comprehensive index;[6] nevertheless, it provides
inadequate information about bioavailability and toxicity since mobility, bioavailability, and toxicity of heavy
metals have close correlations with their speciation.[7]
Therefore, some researchers have suggested that total
contents of heavy metal are not the best indicators
of their bioavailability and toxicity.[8 – 11] In order to
address this issue, sequential extraction (or fractionation) procedures have been developed predominantly
to determine the amounts and proportions of metals
present in different forms in sediment samples.[12,13]
Baihua Lake and Aha Lake, located on the Yungui Plateau in southwestern China, are two of the
five drinking-water sources for approximately three
million population of Guiyang City, the capital of
Guizhou Province. They are both multi-functional water
systems not only for drinking-water provision, but
for flood control, shipping, and fishery as well. Baihua Lake (E 106◦ 27 –106◦ 34 , N 26◦ 35 –26◦ 42 ) is
located in Qingzhen County and is only 16 km west
of Guiyang City. It is a man-made lake built in the
1960s when the second cascade hydropower station
was established on Maotiao River, a major tributary of
Wujiang River. The lake covers an area of 14.5 km2 and
636
X. HUANG ET AL.
holds 191 million m3 of water. There are seven headstreams flowing into the lake, which are Dongmenqiao,
Changchong, Maicheng, Maixi, Dayuanba, Shangmaixi,
and Nanmen Streams. Aha Lake (E 106◦ 37 –106◦ 40 ,
N 26◦ 30 –26◦ 34 ), built in 1950s, is located only 8 km
southwest of Guiyang City. The lake covers an area of
3.4 km2 and holds 86.6 million m3 of water. Aha Lake
is situated on a tributary of River Nanming and five
headstreams converge here, which are Youyu, Baiyan,
Sha, Lanni, and Caichong streams. In recent decades,
with the development of various industries, urbanization, and agriculture in surrounding areas, the two lakes
have been polluted with various pollutants, e.g. heavy
metals. Baihua Lake is surrounded by rapidly expanded
towns like Qingzhen City and high-pollution industry
such as metal, chemical, and power plants, whereas Aha
Lake is especially close to hundreds of deserted small
coal mines. These should significantly add to heavy
metals and other contaminants loading in the two lakes.
Heavy metals pollution in the two lakes has stirred
up strong concerns among researchers and several studies have already been carried out. Hou et al . reported
the different species of mercury in the overlaying water
of Baihua Lake.[14] In their study, mercury was classified as reactive, dissolved, and particulate mercury.
Huang et al . investigated the mercury pollution in sediments from Baihua Lake, indicating that the loading
of the element was still high. The mercury pollution in
Baihua Lake has been well known among local communities and believed to be caused by the past discharges
from a nearby organic chemical company which used
to produce acetaldehyde by employing the mercurycontaining catalysts.[15] Bai et al . studied the concentration and distribution of different mercury species in
the water columns and sediment pore-water of Aha
Lake.[16] Hitherto, no data or information concerning
speciation of chromium (Cr), copper (Cu), and zinc
(Zn) in sediments from Baihua Lake or Aha Lake were
reported. The main objectives of the present research
were to study the speciation of three heavy metals
(Cr, Cu, and Zn) in sediments from Baihua Lake and
Aha Lake based on the sequential extraction procedure
developed by Tessier et al ., and to clarify the distribution characteristics of these metals in different chemical phases. In addition, organic matters (OM) which
contains numerous functional groups for the complexation of trace metals was also investigated in sediments
since it plays an extremely important role in partitioning
behavior of heavy metals.[17]
EXPERIMENTAL
Materials and methods
The sediment samples used in this study were collected
during November 2007 in Baihua Lake and Aha Lake
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pacific Journal of Chemical Engineering
Distribution of sampling sites in Baihua
Lake. This figure is available in colour online at
www.apjChemEng.com.
Figure 1.
Figure 2. Distribution of sampling sites in Aha
Lake. This figure is available in colour online at
www.apjChemEng.com.
(Figures 1 and 2). Superficial sediments were taken with
a grab-sampler at 20 locations which were selected
based on the size, shape, and water-flowing direction
of the two lakes. In Baihua Lake, sediment samples
were collected from locations of Dachong, Yueliangwan, Meituwan, Pingpu, Laojiutu, Tieshuizhan, Longtan, Yapengzhai, Jiangjiapu, and Guanyinshanzhuang.
In Aha Lake, sediment samples were collected from
locations of Caijiaguan, Daba, Dababian, Huachong,
Zhufangba, Kailongzhai, Zhufangbabian, Lusidayan,
Dahuangpo, and Mawozhai. Samples were put in glass
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering
SPECIATION OF HEAVY METALS BAIHUA LAKE AND AHA LAKE
bottles (1000 cm3 volume) that were pre-cleaned with
5% HCl (v/v) and 5% HNO3 (v/v), and immediately
transported to the laboratory. In our laboratory, the
sediments were centrifuged and the supernatants were
discarded. The resulting sediment materials were dried
at room temperatures and then ground into powder for
analysis. At the same time, 3.0000 g of each sediment
sample powder was dried at 105 ◦ C for 24 h to determine moisture.
Instruments and reagents
The following instruments were used in this research:[1]
inductively coupled plasma atomic emission spectrometry (ICP-AES, Optima 5300V) made by Perkin Elemer Corporation from USA;[2] water purification system (Nex Power 2000) by Human Corporation from
Korea;[3] immersion oscillator (SHZ-C) by Shanghai
Yuejin Medical Instruments Company from China. All
reagents used in this study were made in China. The
hydrochloric acid (HCl), nitric acid (HNO3 ), and perchloric acid (HClO4 ) were guaranteed reagents, and the
other reagents were with analytical grade.
Analytical procedures
Analysis of total amount of heavy metals in
sediments from the two lakes
To analyze the total amount of heavy metals in sediment from the two lakes, 0.5000 g of each sediment
sample was weighed accurately in a 250-ml beaker
and 20 ml of digesting mixture made up of concentrated nitric acid and concentrated perchloric acid
[nitric acid: perchloric acid = 4 : 1 (V/V)] was added.
The beakers were placed on an adjustable electric heating plate, and heated with low temperature for ca
60 min; then the electric heating plate was adjusted to
the highest temperature and the heating was continued
until a small amount of solution was left and the color
of sediment was changed to the white. The remaining
solution and sediment were transferred into a 50-ml volumetric flask and diluted to the full volume with 0.5%
(V/V) nitric acid solution. The solutions prepared above
were used to determine the total amount of Cr, Cu, and
Zn with ICP-AES.
Chemical fractionation of heavy metals in
sediments by sequential extraction procedure
First step (Exchangeable fraction, F1 ): 1.0000 g of each
sediment sample was weighed accurately in 100-ml
centrifuge tube, and 15 ml of 1 mol/l MgC12 solution
was added. Thereafter, the mixture was shaken on
the oscillator mentioned above at 30 rpm at room
temperature for 2 h. The extract was separated from
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
the solid residue by centrifugation at 3000 × g for
20 min. The supernatant was decanted and collected for
analysis. The residue fraction was washed by adding
20 ml of deionized water, shaking for 15 min on the
oscillator, and centrifuging for 20 min at 3000 × g. The
supernatant was decanted and discarded, and the residue
was reserved for the analysis of next step. Second step
(Bound to Carbonates fraction, F2 ): Fifteen milliliters
of 1 mol/l NaOAc was added to the residue from the
first step. The mixture was shaken on the oscillator at
30 rpm at room temperature for 2 h. The extract was
separated as performed in the first step, the residue was
washed as in the previous step, and the supernatant was
decanted and discarded. Third Step (Reducible Fraction,
F3 ): Twenty milliliters of 0.04 mol/l NH2 OH · HCl in
25% HOAc was added to the residue from the second
step. The mixture was shaken on the oscillator at 30 rpm
at 85 ± 2 ◦ C for 3 h; then another 10 ml of NH2 OH ·
HCl was added and the resulting mixture was shaken
for another 2 h. The extract was separated as in the first
step, the residue was washed as in the previous step, and
the supernatant was decanted and discarded. Fourth step
(Oxidizable fraction, F4 ): Three milliliters of 0.02 mol/l
HNO3 and 5 ml of 30% H2 O2 were added to the residue
from the third step, and the pH value was adjusted to 2.0
with HNO3 . About 1 h later, The mixture was shaken
on the oscillator at 30 rpm at 85 ± 2 ◦ C for 2 h; then
an additional 3 ml of 30% H2 O2 (the pH value was
adjusted to 2.0 with HNO3 ) was added and the mixture
was shaken on the oscillator at 30 rpm at 85 ± 2 ◦ C for
3 h. The extract was separated as in previous steps and
the residue was discarded. Residual fraction (F5 ) was
equal to the difference between the total content and
the sum of the former four fractions. At the same time,
the blanks were measured in parallel for each set of
analysis using the extraction reagents described above.
Analytical procedure of organic matter in
sediments
OM was determined as a loss on ignition at 550 ◦ C in
12 h to obtain constant weight.
RESULTS AND DISCUSSION
Total concentrations of heavy metals in
sediments from the two lakes
The total concentrations of each heavy metal in the 20
sediment samples are listed in Table 1. Concentrations
of each heavy metal (C) are calculated with the following equation:
C =
(Cs × V )
M × (1 − Pm )
where CS stands for the measured concentration of
each heavy metal in solution prepared from a sediment
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
DOI: 10.1002/apj
637
638
X. HUANG ET AL.
Asia-Pacific Journal of Chemical Engineering
sample for analytical procedure; V is the volume of the
solution prepared from the sediment sample; M stands
for the sample weight; Pm is the percentage of moisture
in the sample. As shown in Table 1, it is obvious that
the concentrations of Zn in sediment samples from Aha
Lake were higher than those from Baihua Lake, and
concentrations of Cr and Cu did not show significant
difference between the two lakes.
In sediment samples from Baihua Lake, the concentrations of Cr, Cu, and Zn ranged from 27.2
to 78.7 mg/kg, 45.9 to 116.0 mg/kg, and 78.6 to
449.6 mg/kg, and the mean values were 59.7, 74.9,
and 283.6 mg/kg, respectively. All of the three elements
were at low concentrations at sampling site Meituwan
and high concentrations at sampling site Jiangjiapu.
Because the sampling site Meituwan is located in the
middle of the lake, contaminants from headstreams
could not reach there easily but were mostly deposited
in the upper part of the lake, whereas there was a headstream named Lannigou flowing into the Baihua Lake
at the sampling site Jiangjiapu; this could be why all of
the three elements presented higher concentrations here
than at site Meituwan.
In the sediment samples from Aha Lake, the concentrations of Cr, Cu, and Zn ranged from 40.6
to 100.4 mg/kg, 34.0 to 96.2 mg/kg, and 204.5 to
689.3 mg/kg, and the mean values were 56.9, 65.4, and
386.6 mg/kg, respectively. At the sampling site Daba,
Cr was present at a high concentration of 100.4 mg/kg,
which was nearly one time higher than at other sampling
Table 1. Amount of Cr (mg/kg), Cu (mg/kg), Zn (mg/kg),
and OM (%) in sediments from Baihua Lake and Aha
Lake.(dry weight, dw).
Sampling sites
Baihua Lake
Dachong
Yueliangwan
Meituwan
Pingpu
Laojiutu
Tieshuizhan
Longtan
Yapengzhai
Jiangjiapu
Guanyinshanzhuang
Aha Lake
Caijiaguan
Daba
Dababian
Huachong
Zhufangba
Kailongzhai
Zhufangbabian
Lusidayan
Dahuangpo
Mawozhai
Cr
Cu
Zn
OM
67.0
59.3
30.8
27.2
72.2
73.3
61.6
60.4
78.7
67.0
74.7
71.1
47.8
83.1
95.7
74.9
68.3
45.9
72.2
116.0
325.0
324.9
214.4
262.4
331.5
219.4
251.5
178.6
449.6
278.5
11.91
13.21
14.27
13.18
11.71
14.70
17.38
18.02
12.08
11.62
42.9
100.4
54.3
51.4
58.9
59.1
40.6
50.6
46.7
63.6
34.0
92.3
39.5
58.1
64.9
96.2
92.2
53.8
87.6
34.9
234.4
204.5
223.3
285.8
581.9
689.3
507.7
457.3
455.9
226.0
10.62
12.55
12.79
11.81
10.95
13.90
13.50
12.54
10.88
10.62
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
sites, and that could be caused by serious pollution from
untreated urban sewage discharged from nearby towns
and villages. Cu and Zn presented similar distribution
characteristics which indicated that the concentrations
in the southern part of the Aha Lake were higher than
those in the northern part, except for the sampling site
Mawozhai. To our knowledge, there were a large number of small coal mines distributed around the southern part of the lake, from which wastewater discharges
should be partly responsible for this pollution.
Distributing characteristics of organic matter
in sediments
The contents of OM in sediments from Baihua Lake
were high in comparison with those from Aha Lake
(Table 1). In Baihua Lake, the amounts of OM ranged
from 11.62 to 18.02%, and the average value was
13.81%. The largest value turned up at the sampling
site of Yapengzhai. Following Yapengzhai, the value for
the sampling site Longtan was up to 17.38%. Amounts
of OM in these two sampling sites were much higher
than those in the other sampling sites. At the sampling
site Laojiutu, the OM had the lowest content. Probably, pollution from the nonpoint sources (agricultural
cultivation and fertilization) around Yapengzhai and
Longtan sampling sites were more severe than around
the other sampling sites. Around the sampling sites of
Yapengzhai and Longtan was mainly farming land while
the other sampling sites are surrounded by forest and
wasteland.surround. In Aha Lake, amounts of OM in
the sediments ranged from 8.48 to 13.90% and the mean
value was 11.80% lower than that in Baihua Lake.
Speciation of heavy metals in sediments
As shown in Tables 2–4 and Figures 3–5, in some
samples, heavy metal concentrations were not detected
(ND) in certain phases, mainly in the exchangeable one
for Cr; exchangeable, carbonate, and reducible ones for
Cu; and mainly in the exchangeable and reducible ones
for Zn.
It was evident that the residual phase was the most
dominant sink for Cr (57.57–87.46%) in sediments
from both lakes. Carbonate, reducible, and oxidizable
phases were also important phases for this element,
and they, respectively, accounted for 3.93–13.16%,
3.82–14.34% and 4.33–30.76% of its total amount
in the 20 sediment samples. Although there were no
detectable concentrations of Cr in exchangeable phase
of all samples, Cr bound to carbonate (Cr – F2) and
distributed in reducible phase (Cr – F3) presented high
percentages at sampling sites Meituwan and Pingpu
in Baihua Lake and at sampling sites Zhufangbabian,
Lusidayan, and Dahuangpo in Aha Lake. The highest percentage of Cr bound to iron and manganese
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering
SPECIATION OF HEAVY METALS BAIHUA LAKE AND AHA LAKE
Table 2. Speciation of Cr in sediments from Baihua Lake and Aha Lake (dry weight, dw).
Exchangeable
Sampling sites
Baihua Lake
Dachong
Yueliangwan
Meituwan
Pingpu
Laojiutu
Tieshuizhan
Longtan
Yapengzhai
Jiangjiapu
Guanyinshanzhuang
Aha Lake
Caijiaguan
Daba
Dababian
Huachong
Zhufangba
Kailongzhai
Zhufangbabian
Lusidayan
Dahuangpo
Mawozhai
a
Carbonate
Reducible
Oxidizable
Residual
mg/kg
%
mg/kg
%
mg/kg
%
mg/kg
%
mg/kg
%
NDa
ND
ND
ND
ND
ND
ND
ND
ND
ND
–
–
–
–
–
–
–
–
–
–
3.94
3.99
4.05
3.43
4.02
4.49
3.55
3.87
5.86
3.26
5.88
6.73
13.16
12.65
5.56
6.13
5.76
6.40
7.45
4.87
4.20
4.01
3.99
3.89
3.83
4.56
3.64
3.52
6.33
3.73
6.27
6.76
12.97
14.34
5.30
6.23
5.91
5.82
8.04
5.57
5.65
4.86
4.38
3.88
3.91
11.62
18.95
4.65
5.13
2.90
8.44
8.20
14.23
14.31
5.41
15.86
30.76
7.69
6.52
4.33
53.16
46.44
18.35
15.92
60.49
52.58
35.47
48.41
61.37
57.06
79.40
78.31
59.64
58.70
83.72
71.78
57.57
80.08
77.99
85.23
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
–
–
–
–
–
–
–
–
–
–
3.63
3.95
3.96
3.64
3.80
4.27
4.15
4.24
4.23
3.92
8.46
3.93
7.29
7.08
6.45
7.23
10.23
8.38
9.06
6.17
3.76
3.84
3.76
3.95
4.16
4.58
4.35
5.18
4.80
3.84
8.76
3.82
6.92
7.69
7.06
7.75
10.73
10.24
10.28
6.04
2.41
4.80
3.82
4.68
4.83
5.90
5.13
4.88
5.13
3.23
5.62
4.78
7.03
9.11
8.20
9.99
12.65
9.65
10.99
5.08
33.11
87.81
42.79
39.11
46.10
44.33
26.92
36.27
32.54
52.58
77.16
87.46
78.76
76.12
78.28
75.03
66.39
71.72
69.68
82.71
ND: Not detected
Table 3. Speciation of Zn in sediments from Baihua Lake and Aha Lake.
Exchangeable
Sampling sites
Baihua Lake
Dachong
Yueliangwan
Meituwan
Pingpu
Laojiutu
Tieshuizhan
Longtan
Yapengzhai
Jiangjiapu
Guanyinshanzhuang
Aha Lake
Caijiaguan
Daba
Dababian
Huachong
Zhufangba
Kailongzhai
Zhufangbabian
Lusidayan
Dahuangpo
Mawozhai
a
Carbonate
mg/kg
%
mg/kg
%
NDa
ND
ND
ND
ND
ND
ND
ND
ND
ND
–
–
–
–
–
–
–
–
–
–
25.0
49.4
28.0
15.2
28.3
10.2
12.4
6.8
9.7
8.1
7.69
15.22
13.06
5.79
8.54
4.65
4.93
3.81
2.16
2.91
ND
ND
ND
ND
ND
ND
ND
0.7
ND
ND
–
–
–
–
–
–
–
0.15
–
–
7.8
8.2
1.9
7.3
7.2
20.8
25.9
18.7
28.0
13.5
3.33
4.02
0.85
2.55
1.24
3.02
5.10
4.09
6.14
5.97
Reducible
mg/kg
Oxidizable
Residual
%
mg/kg
%
mg/kg
%
0.6
2.4
1.1
0.2
2.1
ND
0.5
ND
1.3
1.3
0.18
0.74
0.51
0.08
0.63
–
0.20
–
0.29
0.47
51.9
36.7
35.6
27.7
27.5
38.7
50.4
31.8
56.3
33.4
15.96
11.31
16.60
10.56
8.30
17.65
20.05
17.81
12.53
11.99
247.6
236.0
149.7
219.3
273.4
170.4
188.1
140.0
382.2
235.8
76.16
72.73
69.82
83.57
82.52
77.70
74.82
78.39
85.03
84.64
ND
ND
ND
ND
ND
ND
ND
2.1
2.0
ND
–
–
–
–
–
–
–
0.46
0.44
–
11.0
27.8
17.3
22.0
69.9
76.8
79.7
80.2
77.9
35.3
4.69
13.61
7.75
7.70
12.01
11.15
15.71
17.54
17.09
15.62
215.7
168.2
204.1
256.5
504.7
591.4
401.8
355.6
348.0
177.2
91.98
82.37
91.40
89.75
86.75
85.83
79.19
77.76
76.33
78.41
ND: Not detected
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
DOI: 10.1002/apj
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X. HUANG ET AL.
Asia-Pacific Journal of Chemical Engineering
Table 4. Speciation of Cu in sediments from Baihua Lake and Aha Lake.
Exchangeable
Sampling sites
Baihua Lake
Dachong
Yueliangwan
Meituwan
Pingpu
Laojiutu
Tieshuizhan
Longtan
Yapengzhai
Jiangjiapu
Guanyinshanzhuang
Aha Lake
Caijiaguan
Daba
Dababian
Huachong
Zhufangba
Kailongzhai
Zhufangbabian
Lusidayan
Dahuangpo
Mawozhai
a
Carbonate
mg/kg
%
mg/kg
NDa
ND
ND
ND
ND
ND
ND
ND
ND
ND
–
–
–
–
–
–
–
–
–
–
1.00
0.80
ND
ND
ND
ND
ND
0.52
ND
ND
ND
ND
ND
ND
ND
ND
0.51
0.53
0.52
ND
–
–
–
–
–
–
0.55
0.99
0.59
–
3.05
ND
1.36
ND
ND
ND
1.40
3.62
2.00
ND
%
Reducible
Oxidizable
Residual
mg/kg
%
mg/kg
%
mg/kg
%
1.34
1.13
–
–
–
–
–
1.13
–
–
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
–
–
–
–
–
–
–
–
–
–
31.83
29.17
28.46
28.34
35.53
43.78
52.19
15.49
62.83
59.53
42.59
41.04
59.60
34.10
37.13
58.43
76.39
33.73
87.01
51.32
41.91
41.10
19.29
54.78
60.17
31.15
16.13
29.91
9.38
56.47
56.07
57.83
40.40
65.90
62.87
41.57
23.61
65.14
12.99
48.68
8.97
–
3.44
–
–
–
1.52
6.73
2.28
–
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
–
–
–
–
–
–
–
–
–
–
6.09
57.94
10.47
15.08
13.86
14.82
24.51
25.01
41.66
14.10
17.91
62.79
26.49
25.96
21.35
15.40
26.60
46.50
47.56
40.42
24.86
34.33
27.69
43.01
51.05
81.41
65.74
24.63
43.42
20.78
73.12
37.21
70.07
74.04
78.65
84.60
71.33
45.79
49.57
59.58
ND: Not detected
Figure 3. Speciation of Cr in sediments from Baihua Lake
and Aha Lake.
(Cr – F4) was characterized at sampling site Longtan
in Baihua Lake, and that was characterized at sampling
site Zhufangbabian in Aha Lake. The residual fraction
(Cr – F5) showed lower percentages of Cr at sampling sites Meituwan, Pingpu, and Longtan in Baihua
Lake, and at sampling sites Zhufangbabian, Lusidayan,
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Figure 4. Specification of Cu in sediments from Baihua Lake
and Aha Lake.
and Dahuangpo in Aha Lake. Similarly, there was no
detectable Zn in exchangeable phase in the 20 sediments
except the one collected from the sampling site Lusidayan in Aha Lake. The residual phase was again a significant sink for Zn in both the lakes (69.82–91.98%),
and the highest percentage of Zn in residual phase
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering
SPECIATION OF HEAVY METALS BAIHUA LAKE AND AHA LAKE
Table 5. Correlations between OM and each heavy
metal distributed in the oxidizable phase of sediments
from Baihua Lake and Aha Lake.
OM
Cr
Cu
Zn
∗
Figure 5. Specification of Zn in sediments from Baihua Lake
and Aha Lake.
turned up at sampling site Jiangjiapu in Baihua Lake
and at sampling site Caijiaguan in Aha Lake, respectively. In carbonate and oxidizable phases, Zn presented
a minor distribution, accounting for 0.85–15.22% and
7.70–20.05% of the total amount in all samples. In contrast to Cr and Zn, Cu presented its own distribution
characteristics among all of the geochemical phases.
Unlike Cr and Zn, the residual phase for Cu was not the
only single important phase. In oxidizable and residual
phases, percentage of Cu ranged from 15.40 to 87.01%
and 12.99 to 84.60% of the total amount, respectively.
In the other geochemical phases, Cu exhibited a rather
limited distribution (ND – 8.97%). Based on the theory
of the sequential extraction procedure applied in this
study, the heavy metals distributed in the former geological phases have a higher chance to be transferred
into the overlying water than in the latter geological
phases. Therefore, special attention should be paid to
Cr and Zn among the three metals under investigation.
It is known that metals in the oxidizable phase may
be bound to active sites of organic molecules or precipitated as sulfides. With the depletion of the dissolved
oxygen content in the sedimentary environment as a
result of microbiological activity, sulfate is the major
electron acceptor driving OM oxidation in anaerobic
sediments. The generated sulfide [that may be represented by acid volatile sulfide (AVS) in the process
of OM oxidation] is an important ligand, which can
form stable metal sulfide precipitates in sediments, and
thereby governs the behavior of divalent metals.[18 – 20]
Therefore, in deep-water lake or lake with eutrophication, some heavy metals have the tendency to accumulate in oxidizable and residual phases. In the present
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Pearson
Pearson
Pearson
Pearson
correlation
correlation
correlation
correlation
OM
Cr
Cu
Zn
1
0.604∗
0.097
0.004
1
0.367
0.194
1
0.099
1
p < 0.01 level, two-tailed;
research, concentrations of OM in sediments from Baihua Lake were much higher than those from Aha Lake.
This is probably one of the reasons why Cu showed
much higher importance to oxidizable phase of sediments from Baihua Lake than from Aha Lake. The
correlations between OM and each heavy metal distributed in oxidizable phase were analyzed and tabulated
for the 20 sediment samples collected from Baihua Lake
and Aha Lake (Table 5). It is noted that the Pearson’s
correlation coefficient between OM contents and Cr
concentrations in oxidizable phase of the 20 sediments
(fraction χ ) was 0.604 (p < 0.01), although there were
no significant associations between OM contents and
the levels of the other two elements.
On comparison of Baihua Lake and Aha lake with
Poyang Lake in Jiangxi Province and Taihu Lake in
Jiangsu Province, some common characteristics and
differences were evidenced.[21,22] For all the four lakes,
residual phase was only one predominating phase for
Cr and Zn, whereas both the oxidizable and the residual
were important phases for Cu. The differences for those
lakes lie in the exchangeable phase. In Poyang Lake
and Taihu Lake, Cr, Cu, and Zn were all detectable in
the phase. In the present study, however, no detectable
concentrations were found in the exchangeable phase
for Baihua Lake and Aha Lake. These two lakes are
both deep-water lakes (the depth of water was up
to 50 m at some sites), whereas Poyang Lake and
Taihu Lake are shallow ones. In addition, Baihua Lake
and Aha Lake are both carbonate karst reservoirs.
Probably, such distinctive characteristics have caused
the differences.
CONCLUSIONS
The results obtained from the present study have
afforded an important bearing on metal bioavailability
and toxicity to aquatic biota, particularly to those
organisms living in the sediment environment. To
conclude, Cu was mainly bound to the oxidizable and
residual phases in the sediments from the two lakes, and
showed a rather limited distribution in exchangeable,
carbonate, and reducible phases; therefore, Cu posed a
much lower risk to the water body in normal conditions
Asia-Pac. J. Chem. Eng. 2009; 4: 635–642
DOI: 10.1002/apj
641
642
X. HUANG ET AL.
Asia-Pacific Journal of Chemical Engineering
because of its low mobility in the sediment environment
coming from diagenetic processes. Zn and Cr would
be the critical elements in terms of hazard to the
lakes created by the heavy metals under investigation,
because they are more easily translocated and absorbed
by benthos owing to their distribution in carbonate or
reducible phase
Acknowledgements
This work was supported by the Government of
Guizhou Province (Projects No. [2007]400126 and No.
TZJF-2006-27) and the Chinese Ministry of Education
(Project No. 206135).
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